Study: Blue whales don’t recognize danger from massive cargo ships

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FILE – In this Aug. 14, 2008 file photo provided by Cascadia Research, a blue whale is shown near a cargo ship in the Santa Barbara Channel off the California coast. Cargo ships will be paid to slow down to avoid hitting whales and cut air pollution, under a new voluntary program being launched off California. (AP Photo/Cascadia Research, John Calambokidis, File)

Blue whales are unconcerned about the massive cargo ships that sometimes strike them because they simply don’t recognize the danger they pose, according to new results of an ongoing study.

“It’s not part of their evolutionary history to have cargo ships killing them, so they haven’t developed behavioral responses to this threat,” said Jeremy Goldbogen, an assistant professor at Stanford’s University’s Hopkins Marine Station in Pacific Grove and senior author of a study on the matter.

The study argues that blue whales never had an opportunity to learn to be afraid of massive ocean liners so, at best, the react slowly when a ship approaches. Researchers suggest reducing ship speeds to protect blues, humpbacks, fins and other whales species that frequent the area in search of food.

Whales observed for the study either dived just beneath the surface when ships approached, or ignored them altogether.

“Our analysis suggests that the ability of blue whales to avoid ships is limited to relatively slow descents, with no horizontal movement away from a ship,” the report states. “This is likely a factor in making blue whales, and perhaps other large whales, more vulnerable to ship strikes.”

Last year, a statewide program initiated financial incentives for shippers that slow down through known whale feeding areas between Point Conception and the ports of Los Angeles and Long Beach. Ship routes through these areas also were slightly altered in an attempt to avoid areas the animals frequent.

In 2007, four blue whales were found dead after they were hit by ships in and around the Santa Barbara Channel. Two blue, one humpback and two fin whales died as a result of collisions with ships along the north-central California coast in 2010. And in February, a 50-foot-long fin whale died when it was hit by the Ever Dainty — an Evergreen container ship from Panama — and was inadvertently dragged into the Port of Los Angeles because it got stuck on the ship’s bow.

In April, a 56-foot dead fin whale with injuries consistent with a ship strike turned up in the Port of Los Angeles.

On May 4, a dead humpback whale washed up on Pacifica beach with ship-strike injuries. Researchers say that, while they only studied blues, humpbacks and fins are susceptible to the same problem. After all, they’re some of the largest animals in the ocean and rarely face predators.

Phil Clapham, leader of the Cetacean Assessment and Ecology Program at NOAA’s National Marine Mammal Laboratory in Seattle, said it’s an important study.

“It’s the first time anyone has linked whale- and ship-tracking data to see how whales react to vessels passing close by,” he said. He compares reducing ship speeds to lowering the speed limit in school zones. “The time available to react and get out of the way can be the difference between survival and mortality — whether it’s for a whale or a first-grader.”

With adults up to 100 feet long and weighing up to 200 tons, blue whales are the largest animals that ever roamed the Earth — bigger, even, than Argentinosaurus, the beefiest of the dinosaurs. They dine on krill, tiny shrimplike creatures that thrive in coastal waters, each feasting on thousands of pounds of the crunchy crustaceans a day. But they’re slow divers, according to the study — even when homing in on food, they dive about 4 to 6 feet per second.

Goldbogen and his colleagues wanted to learn just what these behemoths do when ships approach. The researchers tagged hundreds of blue whales with GPS sensors and tracked the movements of nearby ships. They focused on waters near the ports of Los Angeles and Long Beach, together the second-largest commercial harbor in the U.S. Studies estimate that 2,000 to 3,000 blue whales inhabit the Pacific Coast from Costa Rica to Alaska, many of which travel to Southern California in the summertime.

Over the course of four summers, the researchers noted 20 “close calls” between ships and nine individual whales. The whales’ responses to rumbling ships were inconsistent. Many didn’t respond at all. Some dove, but even slower than usual.

When blue whales dive for krill under normal circumstances, they tend to accelerate to gather momentum, then angle down sharply and zoom down into the depths, said John Calambokidis, research biologist at the Cascadia Research Collective in Olympia, Wash., and co-author of the study. But when threatened by ships, he and his colleagues observed, whales simply pivoted and sank at a shallower angle and slower speed than normal.

“The key implication for this,” Calambokidis said, “is that it only got away from the ship at a pretty slow rate.” Some whales even dove underneath the ship, rather than out and away from its path.

Ships travel an average of 20 mph, and whales’ slow dives don’t always afford them enough time to traverse the 30 or so feet needed to clear the hull and the suction created by propellers.

Until only recently in geologic history, the researchers said, these mammals never encountered anything so large or dangerous as a ship.

“These are animals that have supremely evolved for living in the marine environment for millions of years,” Calambokidis said. And if a strike is fatal, the individual never gets the opportunity to adapt.

Fifty years after hunting blue whales was banned internationally, the species is still listed as endangered. It’s unclear if collisions with ships threaten its recovery, mainly because it’s unknown how many die in ship strikes. Most whale carcasses sink to the sea floor, rather than floating or washing ashore. Plus, some freighters are so enormous — even compared to the whales themselves — that the crew “might be unaware that they’ve struck a whale that big,” Calambokidis said.

Blue whales also are an important part of tourism in California. Roger Thomas, captain of the San Francisco-based whale-watching ship The Salty Lady, said the blue-gray giants captivate his clients.

“When the sun’s out, they shine,” he said. “It’s quite a thrill to see them up close.”

Calambokidis agreed.

“This is a species of unique attributes — the largest animal that’s ever lived,” he said. “I think we want to coexist with it in a way that allows it to survive.”